Excillum MetalJet D2+ - Alignment Procedure Does Not Converge; No Electron-Dump Signal; Heating Current to Exit Window Reaches Set Value, But the Voltage Value is About Zero; Jet Pressure Fluctuates Violently Between Almost Zero and <200 bar

METALJET D2+ MALFUNCTION AND TROUBLESHOOTING
Revision 19, November 2016 Page 8-2
Problem/Symptom
Possible cause
Remedy
Alignment procedure does not
converge
No electron-dump signal
HV feedthrough insufficiently
aligned
Follow service manual
instructions to
Align HV feedthrough
Electron-dump aperture
contaminated by liquid-metal
debris
Follow service manual
instructions to
Remove liquid-metal debris from
electron-beam dump aperture
No electron-dump signal due to
short circuit by liquid-metal debris
or improper mounting
Follow service manual
instructions to
Remove liquid-metal debris from
electron-beam dump aperture
Heating current to exit window
reaches set value, but the voltage
value is about zero
Exit window short circuited
Follow service manual
instructions to
Replace exit window
Jet pressure fluctuates violently
between almost zero and <200
bar
Pulsation dampener broken
Follow service manual
instructions to
Replace pulsation dampener
Jet pressure fluctuates more
slowly (and possibly irregularly)
and with smaller amplitude than
above
Check valves not tight due to dirt,
wear, or damage
Knock on inlet check valve
housing to remove dirt – if jet
pressure does not stabilize, follow
service manual instructions to
Replace inlet check valve
Jet pressure does not reach set
value
Not enough liquid metal in system
Follow service manual to
troubleshoot the jet system
Check valves not tight due to dirt,
wear, or damage
Jet pressure close to zero with
pump frequency at 50 Hz
Ball in inlet check valve stuck in
seat
Follow service manual to
troubleshoot the jet system
Not enough liquid metal in system
Air is trapped inside pump head
Roughing pump does not reach
below 3 mbar
Water condensation inside
roughing pump
Follow service manual
instructions to
Introduce ballast load
Roughing pump due for service
Follow service manual
instructions to
Replace roughing pump
Turbopump does not attain the
final rotation speed (1500 Hz)
within the specified run-up time
Fore-vacuum pressure too high
See remedy for the above
problem
Vacuum leak in the system
Locate leak and seal it
Turbopump due for service
Follow service manual
instructions to
Replace turbopump